1. Field of the Invention
The present invention relates to a tilting pad type journal bearing.
2. Description of the Related Art
The slide bearing is a shaft bearing that supports a rotary shaft via a thin fluid film. The slide bearings have higher load bearing performance compared to rolling bearings and also excel in vibration damping properties and shock resistance. Therefore, the slide bearings are widely employed for industrial rotary machines (steam turbines, generators, gas turbines, compressors, etc.) required to have high reliability. Tilting pad type journal bearings, excelling in oscillation stability, are well known as a type of slide bearings used for these rotary machines.
The tilting pad type journal bearing comprises a plurality of pads which are arranged along the periphery of a rotary shaft and a bearing housing which supports the pads in a tiltable manner via a plurality of pivots. Lubricating oil is supplied to the gaps between the peripheral surface of the rotary shaft and sliding surfaces of the pads to form oil films, and the rotary shaft is supported by the pressure of the oil films. Since the tilting angle of each pad changes according to the pressure distribution of the oil film, unstable oscillation such as the so-called “oil whip” can be suppressed.
The tilting pad type journal bearings can be roughly classified into two types: the oil bath type and the direct oil supply type. In the oil bath type, the lubricating oil is supplied to the gaps between the peripheral surface of the rotary shaft and the sliding surfaces of the pads by increasing the sealability of the bearing chamber accommodating the pads and storing the lubricating oil in the bearing chamber. In contrast, in the direct oil supply type, the lubricating oil is supplied to the gaps between the peripheral surface of the rotary shaft and the sliding surfaces of the pads via nozzles arranged between the pads, for example (see JP-2004-197890-A, for example).